Benzodiazepine-Free Cardiac Anesthesia for Reduction of Postoperative Delirium (B-Free): A Protocol for a Multi-centre Randomized Cluster Crossover Trial
Bibliographic record
Abstract
Delirium is common after cardiac surgery and associated with adverse outcomes. Benzodiazepine administration before and after cardiac surgery is associated with delirium; guidelines recommend minimizing their use. Benzodiazepine administration during cardiac surgery remains common because of recognized benefits. B-Free is a randomized cluster crossover trial evaluating whether an institutional policy of restricted intraoperative benzodiazepine administration (i.e., ≥90% of patients do not receive benzodiazepines during cardiac surgery) compared with a policy of liberal intraoperative benzodiazepine administration (i.e., ≥90% of patients receive ≥0.03 mg/kg Midazolam equivalent) reduces delirium. Hospitals performing ≥250 cardiac surgeries a year are included if their cardiac anesthesia group agrees to apply both benzodiazepine policies as per their randomization and patients are assessed for postoperative delirium every 12 hours in routine clinical care. Hospitals apply the restricted or liberal benzodiazepine policy during 12 to 18, four-week crossover periods. Randomization for all periods takes place in advance of site start-up; sites are notified of their allocated policy during the last week of each crossover period. Policies are applied to all patients undergoing cardiac surgery during the trial period. The primary outcome is the incidence of delirium up to 72 hours after surgery. B-Free will enrol ≥18,000 patients undergoing cardiac surgery at 20 hospitals across North America. Delirium is common after cardiac surgery and benzodiazepines are associated with the occurrence of delirium. B-Free will determine whether an institutional policy restricting the administration of benzodiazepines during cardiac surgery reduces the incidence of delirium after cardiac surgery.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.024 | 0.028 |
| Meta-epidemiology (narrow) | 0.005 | 0.003 |
| Meta-epidemiology (broad) | 0.009 | 0.005 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.003 | 0.002 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.006 | 0.007 |
| Insufficient payload (model declined to judge) | 0.051 | 0.007 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".